1. Technical Field
The present invention relates to a flat discharge lamp and a production method thereof, and particularly to flat discharge lamp wherein a third electrode is disposed between two distinct electrodes and a production method thereof.
2. Description of Related Art
Conventionally, general flat discharge lamps use incoherently emitting radiation sources for emitting different tones of light, to connect two dielectric electrode plates of a radiator to the two terminals of an AC (Alternate Current) voltage source, and cause the inert gas in the discharge chamber to generate discharge having plasma phenomenon due to the high voltage between the two electrode plates, resulting in the fluorescent medium in the discharge chamber tube being excited to achieve illumination effect. However, this type of discharge is prone to cause high temperature on the discharge chamber tube surface layer and therefore needs to use cooling tube to dissipate the heat. Also, the illumination efficiency of the radiator is affected because of high temperature.
In order to solve the aforementioned problem, U.S. Pat. No. 5,994,849 discloses an operating method of a flat discharge lamp having a structure as shown in FIG. 1A and FIG. 1B. The flat discharge lamp 10 has a flat shaped discharge chamber 11, wherein the discharge chamber 11 is filled with an inert gas 130, and on one surface of the discharge chamber 11 is disposed a plurality of collocated first electrodes 141 and second electrodes 142. The two terminals 161 and 162 of an AC voltage source 16 coupled to the first electrodes 141 and the second electrodes 142 cause a three-dimensional discharge inside the discharge chamber 11 via the voltage pulse sequence provided by the AC voltage source 16. In particular, the three-dimensional discharge is at a distance from the inner wall of the discharge chamber 11, so as to avoid direct discharge on the inner wall surface of the discharge chamber 11. Although the three-dimensional discharge provided by this prior art patent serves to reduce the problematic high temperature at the inner wall of the discharge chamber 11 by keeping a distance from the discharge chamber inner wall, the heat generated through discharge is still clustered in the discharge chamber and can not be effectively removed. Furthermore, during discharge, there exists no boundary between the two electrodes, causing the electric field between the two electrodes to weaken, thereby rendering the illumination intensity of the flat discharge lamp 10 unstable.